A tetragonal molecular cage and polymeric macrocyclic complex based on a clip-like bis-pyridyl-bis-amide ligand.

Reactions of a bis-pyridyl-bis-amide ligand, N,N′-bis(pyridin-3-yl)-2,6-pyridinedicarboxamide (bppdca) with nickel(II) and cobalt(II) salts resulted in a tetragonal molecular cage, [Ni2(bppdca)4(SCN)4] (1), and a 1-D polymeric macrocyclic complex, [Co(bppdca)(SO4)(CH3OH)(DMF)] n ·nCH3OH (2) (DMF = N,N′-dimethylformamide). Compound 1 features a tetragonal cage-like structure. In each cage, four bppdca ligands are twisted in the same direction, which endow the cage with chirality. However, because the twist or screw directions of adjacent cages are contrary, 1 is a mesomer and exhibits no chirality on the whole. Compound 2 possesses a 1-D, double-chain structure containing Co4(SO4)4(bppdca)2 macrocyclic subunits. [ABSTRACT FROM PUBLISHER]